1. Field of the Invention
This invention relates to a paper sheet delivery/stacking apparatus used in a system for processing paper sheets such as bank notes and having means for controlling movement of a pressure plate which presses the paper sheets against a delivery/stacking portion.
A paper sheet delivery/stacking apparatus covers the concept of a paper sheet delivery apparatus, a paper sheet stacking apparatus and an apparatus which performs the functions of both delivering and stacking paper sheets.
A paper sheet delivery/stacking apparatus is incorporated in a paper sheet processing system such as a bank transaction processing system which automatically performs transactions for deposits and withdrawals, an automated teller's machine which handles bank notes or the like.
2. Description of the Prior Art
FIG. 5 illustrates the structure of a paper sheet delivery/stacking apparatus according to the prior art. Paper sheets 11, which are bank notes, by way of example, are placed on a base plate 12 of an accommodating portion longitudinally thereof and are stacked on their long or short sides, with their upper portions tilted slightly to the rear. The paper sheets 11 are sandwiched between a pressure plate 13 and a delivery/stacking portion.
The delivery/stacking portion includes a delivery/stacking roller 16 in contact with the foremost paper sheet 11, a roller 14 which stacks one paper sheet 11, and a roller 15 which delivers one paper sheet 11. The stacking roller 14 is supported on a shaft 18 and is rotatively driven by a motor, not shown, when a paper sheet is stacked. A lever 17 is rockably supported at one end on the shaft 18, and the other end of the lever 17 is rockably connected to one end of another lever 19 by a shaft 20. The delivery/stacking roller 16 is supported on the shaft 20 and is rotatively driven by a motor, not shown. Formed in the other end portion of the lever 19 is an oblong hole 19a extending longitudinally of the lever 19. A pin 21 secured to a frame (not shown) is fitted into the oblong hole 19a and is free to slide therealong. A pressuring spring 24 is stretched between the levers 17 and 19 and urges the delivery/stacking roller 16 in the direction of the paper sheets 11. The delivery roller 15 is rotatively driven by a motor, not shown, when a paper sheet is delivered. An auxiliary roller 22 is in contact with the delivery roller 15.
The pressure plate 13 is supported on a support member 23 and is movable to the left and right along with the support member 23 by a motor, not shown. The contact pressure which the delivery/stacking roller 16 applies to the paper sheets 11 is raised by moving the pressure plate 13 to the left in FIG. 5. Conversely, when the pressure plate 13 is moved to the right, the contact pressure diminishes.
In the delivery/stacking apparatus constructed as set forth above, it is necessary to change the contact pressure of the roller 16 on the paper sheets when the paper sheets are delivered or stacked. When paper sheets are stacked, the pressure plate 13 is moved relatively to the right so that the roller 16 is shifted, by the action of the pressuring spring 24, to the position indicated by the solid line in FIG. 5, whereby the contact pressure of the roller 16 on the paper sheets is weakened. When paper sheets are delivered, the pressure plate 13 is moved relatively to the left so that the roller 16 is shifted to the position indicated by the phantom line in FIG. 5, thereby increasing the contact pressure.
However, with the foregoing arrangement and control of contact pressure, it is not possible to follow up a dynamic pressure change which differs depending upon the number of paper sheets stacked, the quality of the paper sheets or the stacked state of the paper sheets. As a result, jamming of the paper sheets can occur during stacking and the paper sheets may not be delivered correctly. For example, when a paper sheet 11A to be stacked arrives at the roller 16 during the stacking of paper sheets, the roller 16 momentarily moves away from the accommodated paper sheets, as shown by the phantom line in FIG. 6a. However, the roller 16 soon returns in the direction approaching the accommodated paper sheets 11, as indicated by the phantom lines in FIG. 6b, at which time the contact pressure of the roller 16 on the paper sheets momentarily rises. Moreover, the roller 16 is being rotatively driven at this time. As a consequence, the paper sheet 11A is fed in downwardly by an excessive amount and is forced downwardly againt the base plate 12. The end result is an abnormal stacking state.